wireplumber/lib/wp/factory.c

/* WirePlumber
 *
 * Copyright © 2019 Collabora Ltd.
 *    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
 *
 * SPDX-License-Identifier: MIT
 */

/**
 * SECTION: WpFactory
 *
 * The #WpFactory class allows associating a function that is able to construct
 * objects with a well-known name that is registered on the #WpCore
 */

#define G_LOG_DOMAIN "wp-factory"

#include "factory.h"
#include "debug.h"
#include "private.h"

struct _WpFactory
{
  GObject parent;

  GWeakRef core;
  gchar *name;
  GQuark name_quark;
  WpFactoryFunc create_object;
};

G_DEFINE_TYPE (WpFactory, wp_factory, G_TYPE_OBJECT)

static void
wp_factory_init (WpFactory * self)
{
}

static void
wp_factory_finalize (GObject * obj)
{
  WpFactory * self = WP_FACTORY (obj);

  wp_trace_object (self, "destroying factory: %s", self->name);

  g_weak_ref_clear (&self->core);
  g_free (self->name);

  G_OBJECT_CLASS (wp_factory_parent_class)->finalize (obj);
}

static void
wp_factory_class_init (WpFactoryClass * klass)
{
  GObjectClass *object_class = (GObjectClass *) klass;
  object_class->finalize = wp_factory_finalize;
}

/**
 * wp_factory_new:
 * @core: the core
 * @name: the name of the factory
 * @func: the create object callback
 *
 * Returns: (transfer none): the newly created factory. No reference
 *   is passed to the caller, since the reference is held by the core.
 *   The caller is free to ignore the return value
 */
WpFactory *
wp_factory_new (WpCore * core, const gchar * name, WpFactoryFunc func)
{
  WpFactory *f = NULL;

  g_return_val_if_fail (func, NULL);
  g_return_val_if_fail (name != NULL && *name != '\0', NULL);

  f = g_object_new (WP_TYPE_FACTORY, NULL);
  g_weak_ref_init (&f->core, core);
  f->name = g_strdup (name);
  f->name_quark = g_quark_from_string (f->name);
  f->create_object = func;

  wp_debug_object (f, "new factory: %s", name);

  wp_registry_register_object (wp_core_get_registry (core), f);

  return f;
}

/**
 * wp_factory_get_name:
 * @self: the factory
 *
 * Returns: the factory name
 */
const gchar *
wp_factory_get_name (WpFactory * self)
{
  return self->name;
}

/**
 * wp_factory_get_core:
 * @self: the factory
 *
 * Returns: (transfer full): the core on which this factory is registered
 */
WpCore *
wp_factory_get_core (WpFactory * self)
{
  return g_weak_ref_get (&self->core);
}

/**
 * wp_factory_create_object:
 * @self: the factory
 * @type: the object type to construct
 * @properties: a dictionary ("a{sv}") variant with additional properties
 * @ready: (scope async): a callback to call when the object is constructed
 *    and ready
 * @user_data: (closure): data to pass to @ready
 *
 * Calls the #WpFactoryFunc of this factory
 */
void
wp_factory_create_object (WpFactory * self, GType type,
    GVariant * properties, GAsyncReadyCallback ready, gpointer user_data)
{
  wp_debug_object (self, "(%s) create object of type %s", self->name,
      g_type_name (type));

  self->create_object (self, type, properties, ready, user_data);
}

static gboolean
find_factory_func (gpointer factory, gpointer name_quark)
{
  return WP_IS_FACTORY (factory) &&
      WP_FACTORY (factory)->name_quark == GPOINTER_TO_UINT (name_quark);
}

/**
 * wp_factory_find:
 * @core: the core
 * @name: the lookup name
 *
 * Returns: (transfer full): the factory matching the lookup name
 */
WpFactory *
wp_factory_find (WpCore * core, const gchar * name)
{
  GObject *f;
  GQuark q = g_quark_from_string (name);
  f = wp_registry_find_object (wp_core_get_registry (core),
      (GEqualFunc) find_factory_func, GUINT_TO_POINTER (q));
  return f ? WP_FACTORY (f) : NULL;
}

/**
 * wp_factory_make:
 * @core: the #WpCore
 * @name: the name of the factory to be used for constructing the object
 * @type: the object type to construct
 * @properties: a dictionary ("a{sv}") variant with additional properties
 * @ready: (scope async): a callback to call when the object is constructed
 *    and ready
 * @user_data: (closure): data to pass to @ready
 *
 * Finds the factory associated with the given @name from the @core and
 * calls its #WpFactoryFunc with the rest of the arguments to create
 * an object. The new object is notified through the @ready callback.
 */
void
wp_factory_make (WpCore * core, const gchar * name, GType type,
    GVariant * properties, GAsyncReadyCallback ready, gpointer user_data)
{
  g_autoptr (WpFactory) f = wp_factory_find (core, name);
  if (!f) return;
  wp_factory_create_object (f, type, properties, ready, user_data);
}